Complex crystalline picrate explosive containing entrapped amounts of lead azide



3,431,156 COMPLEX CRYSTALLH IE PICRATE EXPLOSIVE nited States Patent CONTAINING ENTRAPPED AMOUNTS OF LEAD AZIDE Joseph F. Kenney, Bridgeport, Conn., assignor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware No Drawing. Filed Oct. 20, 1967, Ser. No. 676,739 U.S. Cl. 14926 37 Claims Int. Cl. C06c 1/02; C07f 7/24 ABSTRACT OF THE DISCLOSURE Novel primary explosives and methods of forming such explosives. All of the new explosives are characterized by a clathrate type structure in which a crystal of a complex picrate explosive serves as a host crystal and entraps Within its crystalline structure large additional amounts of lead azide, and are useful in detonators, primers, fuses and like devices.

BACKGROUND OF THE INVENTION Primary explosives are used in detonators, fuses, primers and like devices, to produce detonation waves capable of exploding quantities of less sensitive secondary explosives used as boosters or even the relatively insensitive high explosives such as ammonium nitrate. The essential requirements of primary explosives are that they explode readily in response to mild, low energy stimuli, such as heat, shock or friction, and yield sufiicient explosive power to dependably initiate other high explosives.

Crystalline lead azide of high purity has long been recognized as a primary explosive having outstanding efficiency in the initiation of other high explosives. However, the handling of high purity lead azide is extremely hazardous and the extraordinary precautions necessary in handling and loading have limited its use.

In efforts to improve the safety in the handling of lead azide, it has been discovered that the addition of dextrin to the solution from which lead azide is precipitated results in the adulteration of the lead azide with a few percent of dextrin. The so-called dextrinated lead azide is comparatively safe to handle but shows a pronounced decrease in initiating power and ignitability.

One important effect of the decreased initiating power of dextrinated lead azide is that more is required to produce good initiation of other explosives than can be fitted into the available space in certain applications. One example is in fuses for small caliber explosive projectiles, where it is not possible to provide space for enough dextrinated lead azide to dependably initiate the shell filler explosive or bursting charge.

Patent 2,421,778 relates to another proposal for increasing the safety of handling lead azide by performing the precipitation in the presence of a dissolved synthetic organic polymer such as polyvinyl alcohol. The so-called PVA lead azide is marginally safer than pure lead azide in some respects and has enjoyed some commercial and governemntal use. However, its crystalline form tends to be elongated and fragile, with the likelihood that small sharp fragments will break off during handling and induce accidental discharge.

Patent 3,291,664 relates to the so-called RD-l333 lead azide which is fairly widely used by or for the United States Government and has enjoyed some commercial success. This explosive is precipitated from an aqueous solution of carboxyr'nethyl cellulose and is also marginally safer than the pure lead azide, with a crystal form which is somewhat superior to PVA lead azide.

Pure lead azide and the almost pure forms of lead azide such as PVA lead azide or RD-1333 lead azide are so ex- 3,431,156 Patented Mar. 4, 1969 tremely sensitive to electrostatic discharge through the crystal mass that they cannot be handled safely using presently available techniques and procedures. Many improper conclusions have been drawn about the electrostatic sensitivity of the various forms of lead azide because of the preference of certain facilities for conducting tests in fixed gap apparatus. A more realistic test is performed with an approaching electrode, which results in an electrostatic discharge directly through the crystalline mass of the explosive. Both methods are described in more detail in the succeeding two paragraphs.

The first of these is a fixed-gap method, in which some of the material to be tested is placed on one of two electrodes and the criteria for evaluating results is the energy released in the discharge through the fixed gap. The electrodes are separated by a fixed gap (usually .005-.010 inch). Voltage sufficiently high to bridge the gap is applied, causing a spark to jump the gap. Lead azide is not very sensitive to this type of discharge. (Wyatt, Moore, Adams and Summer, in the Proceeding of the Royal Society, A246, 1958, report that the point of 50% fires is about 50,000 ergs.)

The second is the approaching electrode method. Here, some of the material to be tested is placed on one of the electrodes; the other is at a distance too great for discharge to take place. The distance is gradually diminished until the second electrode is in contact with the material to be tested and close enough to the first electrode to discharge the voltage through the material. Lead azide is extremely sensitive to this type of discharge. (Fires at energy as low as 20 ergs. are reported in the above reference.)

Tests run by the applicant show 150,000 ergs. to discharge some samples of RD-1333 lead azide at .005 inch gap in the fixed gap apparatus and some samples fired by contact discharge in the approaching electrode apparatus at energies as low as 0.6 erg.

While in the fixed gap test the energy is high enough to make it likely that the cause of explosion of the lead azide is the heat of the spark, in contact discharge, where the energy is so low, it is more probable that the discharge overcomes the electrostatic bonding within the crystal, thereby causing the explosion.

Hereinafter in this application references to electrostatic discharge sensitivity will be understood to refer to contact electrostatic discharge as determined by the approaching eletcrode technique described above. The results shown in this application are tabulated in terms of the voltage to which a 300 mmf. capacitor must be charged to cause explosions by this contact method.

The explosives to which this invention relates have many advantages over either the relatively pure forms of lead azide or the dextrinated lead azide. They are easy to prepare in reproducible form with reproducible explosive characteristics. They are more sensitive to heat and flame and, therefore, do not need a flame sensitive explosive such as normal lead styphnate with them in blasting caps and the like. (Table I) They are stable in the presence of sunlight. They are cheaper. They do not form dangerous copper azide when in contact with copper or copper alloys. While they do not have quite the initiating power of pure lead azide or almost pure forms of lead azide, such as RD-l333 lead azide, they are far superior to dextrinated lead azide and in most cases will give dependable initiation with charges no larger than required when RD-1333 lead azide is used. (Table II) Dextrinated lead azide also occasionally gives unexplained total failures to initiate. Pure lead azide or almost pure forms of lead azide such as RD-1333 lead azide are, as noted above, so sensitive to electrostatic discharge through the crystal mass that it is impossible to handle them with any degree of safety.

Table III compares the sensitivity of these explosives to contact electrostatic discharge. As will be seen, only the dextrinated lead azide is less sensitive to contact electrostatic discharge than the new explosives to which this invention relates when compared to the other explosives listed in these tables.

The new explosives also have quite adequate friction sensitivity (Table IV), being substantially more sensitive than dextrinated lead azide and generally having about the same friction sensitivity as an almost pure form of lead azide such as RD-l333 lead azide.

These and other characteristics of others of the explosives of this invention are listed in the specific examples appended hereto.

Table I.-Instantaneous explosion point Explosive Temp., C. Lead azide (pure, dextrinated or RD1333) value from the published literature 383 Normal lead styphnate 320 (Example 10) 4 (basic lead picrate-lead acetate-lead nitrate-lead azide-11 lead azide 275 (Example 11) 4 (basic lead picrate-lead propionate-lead nitrate-lead azide) '11 lead azide 275 (Example 2) 4 (basic lead picrate-lead acetate-lead azide-l1 lead azide 285 Table II.-Initiating power Detri- RD-1333 High Explosive nated Lead Ex. 10 1 Ex. 11 1 Ex. 2 3

Lead Azide (gr.) (gr.) (gr.) Azide (gr.)

RDX .55 .25 .25 .25 .25 Tetryl .35 25 25 25 25 HMX 4 1. 05 (i5 85 75 75 PETN .35 .25 .25 .25 .25

{at (basic lead pierate-lead acetate-lead nitrate-lead azidelll lead an e.

f (basic lead picrate-lead pr0pi0nate-lead nitrate-lead azide-11 lead a 1 e 1 4 (basic lead picrate-lead acetate-lead azide) -11 lead azide. 4 Not total initiation.

The above quantities are the minimum amounts of the primary explosives needed to fully initiate .90 grain of the high explosives listed. The test piece was a brass cup .21 inch in diameter and .70 inch long.

Table III.Sensitivity to contact electrostatic discharge Explosive: Fires Dextrinated lead azide 0/5 at 7000 volts, 300 MMF;

Footnote at end of table.

Explosive: Fires (Example 2) 4 (basic lead picrate-lead acetate-lead azide) '11 lead azide 0/5 at 1500 volts, 300 MMF;

5/5 at 2000 volts, 300 MMF. N o r m a 1 le a d styphnate (reference) 0/5 at volts, 300 MMF;

5/5 at 200 volts, 300 MMF.

1 This is the low limit of the machine.

Table IV.Friction sensitivity Explosive: 22 inches Dextrinated lead azide 8.80 RD-l333 lead azide 2.08

(Example 10) 4 (basic lead picrate-lead acetate-lead nitrate-lead azide) -11 lead azide (Example 11) 4 (basic lead picrate-lead propionate-lead nitrate-lead azide)-11 lead azide (Example 2) 4 (basic lead picrate-lead acetate-lead azide)-l1 lead azide (Example 1) 4 (basic lead picrate-lead acetate-lead aZide)-6 lead azide 4.50

All samples mixed with 25% glass, 2 oz. weight, Bruceton test of 25 charges of each explosive.

The method of testing the friction sensitivity of these explosives was to mix them with 25% ground glass and subject them to the Bruceton Up and Down method named for the Bruceton Station of the United States Bureau of Mines. More detailed information on this method can be found in a report No. 101.R dated July 1944 and circulated by the Applied Mathematics Panel of the National Defense Research Committee. In this test, a quantity of the explosive mixed with ground glass is contained in a capsule and a fiat faced firing pin is inserted into the capsule in contact with the explosive. The capsule and firing pin are positioned in a drop test apparatus to receive the impact of a ball dropped through suitable guides from known heights. The tabulated values of Y are the values of the height in inches from which a two ounce ball must be dropped to cause the firing of the explosives in 50% of the tests. The exact value is determined by statistical analysis of data accumulated, preferably in testing at the various heights between that at which all charges fire and that at which no charges fire.

RELATED BACKGROUND PATENTS My Patent No. 3,262,956, hereinafter referred to as my 956 patent, issued July 26, 1966, from my application, Ser. No. 340,705, filed Ian. 28, 1964, as a continuation-in-part of my prior application, Ser. No. 190,232, filed Apr. 26, 1962, now abandoned. This patent relates to complex salts of basic lead picrate which combine in characteristic crystalline form definite proportions of basic lead picrate and a combining and precipitating salt selected from the group of lead salts of monobasic acids of no greater acid strength than picric acid, consisting of lead acetate, lead lactate, lead acrylate, lead methacrylate, lead propionate, lead formate, and lead amino acetate. As pointed out in my 956 patent, I was thus able to form such complex salts as the double salts basic lead picratelead formate; basic lead picrate-lead acetate; basic lead picrate-lead propionate; basic picrate-lead lactate; basic lead picrate-lead acrylate; basic lead picrate-lead methacrylate, and basic lead picrate-lead amino acetate.

My Patent No. 3,293,091, hereinafter referred to as my "091 patent, issued Dec. 20, 1966, from my application Ser. No. 339,474, filed Jan. 22, 1964, as a continuation-in-part of my prior applications, Ser. No. 190,237 and Ser. No. 190,238, both filed Apr. 26, 1962 and now abandoned. This patent relates to complex salts of basic lead picrate which combine in characteristic crystalline form definite proportions of basic lead picrate, at least one but not more than two of the lead salts selected from the group of lead salts consisting of lead acetate, lead hy-pophosphite, lead nitroaminoguanidine, lead chlorate, lead azide, lead formate, lead propionate, lead glycolate, lead lactate, lead amino acetate, lead acrylate, lead methacrylate and lead lbutyrate, and one combining and precipitating lead salt selected from the group of lead salts consisting of lead nitrate, lead acetate, lead lactate, lead acrylate, lead methacrylate, lead propionate and lead formate. As outlined in my 091 patent, I found that I was able to produce such complex salts as the triple salt monobasic lead picrate-lead nitrate-lead acetate; Monobasic lead picrate-lead nitrate-lead propionate; and quad ruple salts such as monobasic lead picrate'lead nitrate' lead acetate-lead azide; and monobasic lead picrate-lead nitnate-lead propionate-lead azide; and many other related compounds.

As described in such publications as Chemistry of the Coordination Compounds, John C. Bailar, these are all clathrate compounds:

Clathrates-Another group of molecular compounds in which the geometry of the crystal lattice is of prime importance is the clathrates. These are compounds in which one component is trapped in a cage lattice structure of the second component. It is evident that the ratio of the two components might be integral only in the limiting case, that is, in the event of a perfect lattice where every cage is filled with the requisite number of molecules of the other component.

L111 these compounds, the nature of the trapped component depends not at all on the chemical properties but only on molecular size.

Again, in Websters dictionary, clathrate compounds are defined as Relating to a type of solid molecular compound in which one component is trapped in the cavities of cagelike crystals of another component.

The following quotation from Nonstoichiometric Compounds, Lyon Mandelcorn, Academic Press 1964, is also applicable:

The composition and structure of a nonstoichiometric compound is best considered in terms of the geometrical disposition of one or more of its components. The components may be molecular, atomic, or ionic species. A molecular compound of the host-guest type consists of one component comprising the host structure which contains spaces or cavities that can accommodate the guest molecules. The guest molecules have limited ranges in size and shape to fit the geometry of the cavities. The cavities need not have a simple numerical relationship with the host molecules or atoms.

The 956 patent, above referred to, relates to a class of such compounds in 'Which two separate molecular compounds are combined together in clathrate form in complex solid crystalline form.

The "091 patent, above referred to, relates to a class of such compounds in which as many as four separate molecular compounds are combined together in clathrate form in complex solid crystalline form.

As confirmed by X-ray diffraction and other data submitted in the applications resulting in the patents, the compounds there disclosed are true compounds formed in accordance with true stoichiometric proportions and do not exhibit the nonstoichiometric proportions of some of the clathrate compounds.

DETAILED DISCUSSION OF PREFERRED EMBODIMENTS Subsequent investigations lead to the discovery that it was possible to react these explosives with sodium azide in such a manner as to convert a picrate double salt into a picrate triple salt containing lead azide and a picrate triple salt into a picrate quadruple salt containing lead azide and at the same time integrate into the crystalline structure of the complex picate salts large additional amounts of lead azide. The incorporation of the additional amounts of lead azide does not change the physical appearance of the host crystals, and the new explosives can be differentiated from those of the patent only by X-ray diffraction studies and/ or tests of their explosive characteristics. As in the case of all clathrate compounds, there is a limit beyond which no more lead azide may be accepted within the crystalline structure of the host crystal. The limit was found to be in each case 13 moles of lead azide to 4 moles of the host picrate complex. Beyond this ratio, in each case free lead azide crystals were clearly visible on microscopic examination among the crystals of the new complex compounds. It is obviously desirable to avoid the precipitation of free lead azide crystals among the crystals of the new complex explosive, for the free lead azide crystals, unlike those entrapped within the host crystals, retain all the dangerous electrostatic sensitivity and other dangerous characteristics of pure lead azide. Although the limiting condition without precipitation of free lead azide crystals is 13 molecules of lead azide to 4 molecules of the host complex picrate salt, a practical limit is more like 11 molecules of lead azide to 4 molecules of the host complex picrate salt, for the laboratory procedures necessary to exactly fill the lattice structure of the host picrate complex are most exacting and, as noted above, it is desirable not to precipitate any free lead azide.

The complex salts of the above-identified patents thus appear to have a lattice structure having an ability to serve as host compounds and to accept and retain relatively large amounts of the lead azide molecule up to a definite limiting condition.

The new compounds which are the subject of this patent application have also been investigated by X-ray diffraction techniques and their structure has been identified as comprising a host compound of the complex basic picrate salts disclosed in the applications above-identified having entrapped within the crystal lattice of the host compounds relatively large amounts of lead azide, not necessarily in stoichiometric proportions, provided the lead azide content does not exceed that necessary to complete the filling of the crystal lattice structure of the complex picrate.

SPECIFIC EXAMPLES Specific examples of the explosives produced in accordance with this invention, and procedures for their preparation, are set forth in the following examples:

EXAMPLE 1 [4 (basic lead plcratelead acetate-lead azlde)-6 lead azide] Solution Solute Quantity Number (gms.)

I Picrlc Acid Dissolved 300 cc. H20. 50 cc. H20.

150 cc. H20. cc. H2O.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 'C. for 15 minutes. Filter, wash and dry.

EXAMPLE 2 EXAMPLE 5 [4 (basic lead picratelcad aectatc'lcad azide)-l1 lead azide] [4 (basic lead picrate-lcad nitratelead azide)-11 lead azide] Solution Solute Quantity Dissolved Solution Solute Quantity Dissolved Number (gms) in Number (glIlS.) in

300 cc. H10. 5 9. 2 300 cc. H20. 50 cc. 1120. 4.0 50 cc. H20. 150 cc. H20. 50. 150 cc. H20. 100 cc. 1120. 9. 75 100 cc. H2O.

Add II to I with stirring at 60 to 70 C. Add III over a a minute period. Hold at 60 to 70 C. for minutes. 10 Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for minutes. Filter, wash and dry.

Yield 38 gm. Instantaneous explosion point 285 C. 15 Static sensitivity 0/ 5 fires at 1500 volts, 300 MMF.;

5/5 fires at 2000 volts, 300 MMF. Drop test sensitivity Add II to I with stirring at 60 to 70 C. Add III over 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield Approx. 35.0 gm. 40 Instantaneous explosion point 269 C. Static sensitivity 0/5 fires at 2000 volts, 300 MMF.; 5/5 fires at 2500 volts, 300 MMF. Drop test sensitivity with 25% glass (Bruceton) 3.50". Crystal Form Yellow parallelopipeds. Properties Sensitive, powerful,

primary explosive.

EXAMPLE 4 [4 (basic lead picrate-lead lactate-lead azide)-1l lead azide] Solution Solute Quantity Dissolved Number (gms) in I Picric Acid 9. 2 300 cc. H2O. IL. Sodium Hydroxide. 4. 5 50 cc. H2O. III- 60. 0 150 cc. H 20. IV. 9. 75 100 cc. H10.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 40 gm. Instantaneous Explosion point 267 C. Static sensitivity 0/5 fires at 500 volts, 300 MMF; 5/5 fires at 1000 volts, 300 MMF.

Drop test sensitivity with 25% glass (Bruceton) 2.50". Crystal form Yellow parallelopipeds. Properties Sensitive, very powerful,

primary explosive.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 38 gm. Instantaneous Explosion point 296 C.

Static sensitivity 0/ 5 fires at 1500, volts MMF; 5/5 fires at 2000, volts MMF.

Drop test sensitivity with 25% glass (Bruceton) 1.88".

Crystal form Yellow parallelopipeds.

Properties Sensitive, very powerful,

primary explosive.

EXAMPLE 6 [4 (basic lead picrate-lead metharylate-lead azide)-1I lead azide] Solution Solute Quantity Dissolved Number (gms) in Picric Acid 9.2 450 cc. H2O. Sodium Hydroxide 4. 5 50 cc. H2O. Lead Methacrylate 65.0 Dry. IV Sodium Azide 9. cc. H2O,

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 40 gm. Instantaneous Explosion point 275 C. Static sensitivity 0/5 fires at 4000 volts, 300 MMF; 5/5 fires at 5000 volts, 300 MMF. Drop test sensitivity with 25% glass (Bruceton) 2.04". Crystal form Yellow needles. Properties Sensitive, powerful, primary explosive.

EXAMPLE 7 [4 (basic lead picrate-lead acrylate-lead azideyll lead azide] Solution Solute Quantity Dissolved Number (gms) in- I Picrie Acid 9.2 450 cc. H2O. II 4. 5 50 cc. H2O. III"... 60.0 Dry. IV 9.75 100cc. H20.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Drop test sensitivity with 25% glass (Bruceton) 3.04". Crystal form Yellow parallelopipeds. Properties Sensitive, powerful,

mary explosive.

pri-

EXAMPLE 8 [4 (basic lead picrate-lead iorrnate-lead azide)-II lead azide] Solution Solute Quantity Dissolved Number (gms) in- I Picric Acid 9. 2 450 cc. 1120.

45.0 Dry.

9. 75 100 cc. H1O.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 35 gm. Instantaneous Explosion point 290 C. Static sensitivity /5 fires at 3000 volts, 300

MMF; /5 fires at 3500 volts, 300 MMF. Drop test sensitivity with 25% glass (Bruceton) 2.19". Crystal form Yellow needles.

Properties Sensitive, powerful, primary explosive.

EXAMPLE 9 [4 (basic lead picrate-lead butyrate-lead azide)-11 lead azide] Solution Solute Quantity Dissolved Number (gms) m- I Picric Acid 9. 2 300 cc. H10.

4. 5 50 cc. H20.

60.0 300 cc. H20.

9. 75 100 cc. H20.

Add II to I with stirring 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 1. C. for minutes. Filter, wash and dry.

Yield 40 gm. Instantaneous explosion point 285 C. Static sensitivity 0/5 fires at 2000 volts, 300 MMF; 5/5 fires at 2500 volts; 300 MMF.

Drop test sensitivity with glass (Bruceton) 2.19.

Crystal form Yellow needles. Properties Sensitive, powerful, primary explosive.

EXAMPLE 10 [4 (basic lead picrate-lead acetatelead nitrate-lead azlde)-11 lead azide] Solution Solute Quantity Dissolved Number (gms) in- 300 cc. H20. }50 cc. H20.

150 cc. H20. 100 cc. H20.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, Wash and dry.

Yield 38 gm. Instantaneous explosion point 275 C. Static sensitivity 0/5 fires at 1500 volts, 300

MMF; 5/5 fires at 2000 volts, 300 MMF. Drop test sensitivity with 25 glass (Bruceton) 2.42". Crystal form Yellow parallelopipeds. Properties Sensitive, very powerful,

primary explosive.

EXAMPLE 11 [4 (basic lead plcrate-lead propiongtle-lead nitrate-lead azlde)-l1 lead an e Solution Solute Quantit Dissolved Number (gins) in- I Picrlc Acid 9. 2 300 cc. E20.

Q3 }50 cc. 1120. 50. 0 150 cc. H10. 9. 75 100 cc. H2O.

Add II to I with stirring at 60 to C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 38 gm. Instantaneous explosion point 275 C. Static sensitivity 0/5 fires at 1500 volts, 300 MMF; 5/5 fires at 2000 volts, 300 MMF. Drop test sensitivity with 25% glass (Bruceton) 1.19".

Crystal form Yellow parallelopipeds. Properties Sensitive, very powerful,

primary explosive.

EXAMPLE 12 [4 (basic lead picrate-lcad lactate-lead nitrate-lead azide)-11 lead azide] Solution Solute Quantity Dissolved Number (gms.) in- I gigric Aiiildai .-.a 9.; 300 cc. H10.

0 ium y oxi e 5.

H "{Lactic Acid 4. 2

III Lead Nitrate 50.0 150 cc. H1O.

IV Sodium Azide 9. cc. H1O.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 40 grn. Instantaneous explosion point 285 0. Static sensitivity 0/ 5 fires at 2000 volts, 300 MMF; 5/5 fires at 2500 volts, 300 MMF. Drop test sensitivity with Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 38 gm. Instantaneous explosion point 285 C. Static sensitivity 0/5 fires at 1500 volts, 300 MMF; 5/5 fires at 2000 volts, 300 MMF. Drop test sensitivity with 25 glass (Bruceton) 1.74". Crystal form Yellow parallelopipeds. Properties Sensitive, very powerful,

primary explosive.

EXAMPLE 14 [4 (basic lead picrate-lead aminoacitiaize-lead nitrate-lead azide)-11 lead 82 Solution Solute Quantity Dissolved Number (gms.) in- I Pieric Acid. 9. 2 300 cc. H20.

50 cc. H2O.

50.0 150 cc. H10. 9. 75 100 cc. H2O.

Add II to I With stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for minutes. Filter, wash and dry.

Yield 40 gm. Instantaneous explosion point 270 C. Static sensitivity 0/5 fires at 1000 volts, 300

MMF; 5/5 fires at 1500 volts, 300 MMF. Drop test sensitivity with 25% glass (Bruceton) 2.12". Crystal form Red parallelopipeds. Properties Sensitive, very powerful, primary explosive.

EXAMPLE 15 [4 (basic lead picrate-lead methacyllate-lead nitrate-lead azide)-11 lead Solution Solute Quantity Dissolved Number (gms.) m-

I Picric Acid 9. 2 300 cc. 1120. n Hydreide g3 }50H.0. III. Lead Nitrate 50. 0 150 00. E20. IV 9. 75 100 cc. H20.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 40 gm. Instantaneous explosion point 290 C. Static sensitivity 0/5 fires at 1500 volts, 300

MMF; 5/5 fires at 2000 volts, 300 MMF. Drop test sensitivity with 25% glass Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes. Add IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 40 gm. Instantaneous explosion point 295 C. Static sensitivity O/5 fires at 1500 volts, 300

MMF; 5/5 fires at 2000 volts, 300 MMF.

Drop test sensitivity with 25 glass (Bruceton) 2.65.

Crystal form Yellow parallelopipeds.

Properties Sensitive, v e r y powerful, primary explosive.

EXAMPLE 17 4 (basic lead picrate-lead butyrate-lead nitrate-lead azide)-11 lead azide] Solution Solute Quantity Dissolved Number (gms.) in- I Picric Acid 9. 2 300 cc. H20.

III Lead Nitrate 50. 0 150 cc. H1O.

IV Sodium Azide 9. cc. H2O.

Add II to I with stirring at 60 to 70 C. Add III over a 5 minute period. Hold at 60 to 70 C. for 10 minutes.

All IV over a 5 minute period. Hold with stirring at 60 to 70 C. for 15 minutes. Filter, wash and dry.

Yield 40 gm.

Instantaneous explosion point 295 C.

Static sensitivity 0/5 fires at 6000 volts, 300 MMF; 5/5 fires at 7000 volts, 300 MMF.

Drop test sensitivity with 25% glass (Bruceton) 1.64". Crystal form Yellow parallelopipeds. Properties Sensitive, very powerful, primary explosive.

Referring to Examples 1 through 9 hereof, the similarity of the initial steps of the present process to that of my 956 patent will be apparent. See Examples 1, 4, 10, 12 and 15, of the '956 patent. In each of the Examples 1 through 9, the initial steps of the process through the addition of reagent III produces one of the double salts of the 956 patent, and the crystals thereof are held in suspension as the first three solutions are stirred together. With the addition of sodium azide, however, the suspended crystals of the double salt are redissolved and react with the lead azide formed in the reaction to precipitate crystals of a complex triple salt similar to those disclosed in my 091 patent, having lead azide as one of the constituents of the complex triple salt crystal. At the same time, additional lead azide is entrapped in the crystalline structure of the host crystal up to the limits noted previously herein. Referring to Examples 10 through 17 of this application, it will be noted that the initial steps of these processes are similar to the processes used in my 091 patent to form the complex picrate triple salts. Refer to Examples 1, 6, 7, 9, 10, ll, 12 and 13 of my 091 patent. Through the addition of reagent III in each of Examples 10 through 17 of this application, the process is one which produces the triple salt of my 091 patent, and crystals of those explosives actually form and are held in suspension by the continued stirring. On the addition of the fourth reagent, sodium azide, the triple salt crystals dissolve in the combined solutions and new crystals of a lead azide contaning quadruple picrate salt, such as those disclosed in my 091 patent, are formed. Simultaneously, additional lead azide is also formed and entrapped within the crystal structure of the quadruple salt.

From these similarities to my two issued patents, it should be apparent that the specific examples shown above do not include all of the possible variations of my invention. Accordingly, reference should be made to the appended claims for a more exact definition of the limits of my invention.

I claim:

1. A complex inclusion salt containing in characteristic crystalline for as a host compound a complex picrate salt containing definite proportions of basic lead picrate and lead azide with a lead salt selected from the group of lead salts of monobasic acids consisting of lead nitrate, lead acetate, lead formate, lead propionate, lead lacate, lead acrylate, lead methacrylate and lead butyrate, said complex picrate salt host compound having entrapped within its crystalline structure as a guest compound additional amounts of lead azide up to a ratio of 13 parts of lead azide to each 4 parts of the host compound.

2. A complex inclusion salt as defined in claim 1, said host compound containing in definite proportions lead nitrate and one other lead salt selected from the remaining members of said group of water soluble lead salts.

3. The complex explosive compound 4 (basic lead picrate-lead acetate-lead) -X lead azide, where X is any number up to 13.

4. The complex explosive compound 4 (basic lead pricrate-lead lactate-lead azide) -X lead azide, where X is any number up to 13.

5. The complex explosive compound 4 (basic lead picrate-lead methacrylate-lead azide)-X lead azide, where X is any number up to 13.

6. The complex explosive compound 4 (basic lead picrate'lead methacrylatedead azide)-X lead azide, where X is any number up to 13.

7. The complex explosive compound 4 (basic lead picrate-lead acrylate-lead azide)'X lead azide, where X is any number up to 13.

8. The complex explosive compound 4 (basic lead picrate-lead formate-lead azide) -X lead azide, where X is any number up to 13.

9. The complex explosive compound 4 (basic lead picrate-lead butyrate-lead azide) -X lead azide, where X is any number up to 13.

10. The complex explosive compound 4 (basic lead picrate-lead propionate-lead azide) -X lead azide, where X is any number up to 13.

11. The complex explosive compound 4 (basic lead picrate-lead acetate-lead nitrate-lead azide) -X lead azide, where X is any number up to 13.

12. The complex explosive compound 4 (basic lead picrate-lead propionate-lead nitrate-lead azide)-X lead azide, where X is any number up to 13.

13. The complex explosive compound 4 (basic lead picrate-lead lactate-lead nitrate-lead azide) -X lead azide, where X is any number up to 13.

14. The complex explosive compound 4 (basic lead picrate-lead formate-lead nitrate-lead)-X lead azide, where X is any number up to 13.

15. The complex explosive compound 4 (basic lead picrate-lead aminoacetate-lead nitrate-lead azide) -X lead azide, where X is any number up to 13.

16. The complex explosive compound 4 (basic lead picrate-lead methacrylate-lead nitrate'lead azide) -X lead azide, where X is any number up to 13.

17. The complex explosive compound 4 (basic picrate-lead acrylate-lead nitrate-lead azide) -X azide, where X is any number up to 13.

18. The complex explosive compound 4 (basic picrate-lead butyrate-lead nitrate-lead azide) -X azide, where X is any number up to 13.

19. The complex explosive compound 4 (basic picrate-lead acetate-lead azide) -6 lead azide.

20. The complex explosive compound 4 (basic picrate-lead acetate-lead azide)-ll lead azide.

21. The complex explosive compound 4 (basic picrate-lead lactate-lead azide) 11 lead azide.

22. The complex explosive compound 4 (basic picrate-lead nitrate-lead azide)-11 lead azide.

23. The complex explosive compound 4 (basic picrate-lead methacrylate-lead azide) 11 lead azide.

24. The complex explosive compound 4 (basic picrate-lead acrylate-lead)-1l lead azide.

25. The complex explosive compound 4 (basic picrate-lead formate-lead azide) -11 lead azide.

lead lead lead lead lead lead

lead

lead

lead

lead

lead

26. The complex explosive compound 4 (basic lead picrate-lead butyrate-lead azide) -11 lead azide.

27. The complex explosive compound 4 (basic lead picratelead propionate-lead azide) -11 lead azide.

28. The complex explosive compound 4 (basic lead picrate-lead acetate'lead nitrate-lead azide)-11 lead azide.

29. The complex explosive compound 4 (basic lead picrate-lead propionate-lead nitrate-lead azide)-ll lead azide.

30. The complex explosive compound 4 (basic lead picrate-lead lactate-lead nitrate-lead azide)-11 lead azide.

31. The complex explosive compound 4 (basic lead picratelead formate-lead nitrate-lead azide)-11 lead azide.

32. The complex explosive compound 4 (basic lead picrate-lead aminoacetate'lead nitrate-lead azide)-l1 lead azide.

33. The complex explosive compound 4 (basic lead picrate-lead methacrylate-lead nitrate-lead azide)-11 lead azide.

34. The complex explosive compound 4 (basic lead picrate-lead acrylate-lead nitrate-lead azide)-ll lead azide.

35. The complex explosive compound 4 (basic lead picrate-lead butyrate-lead nitrate-lead azide) -ll lead azide.

36. A method of forming a complex salt of basic lead picrate in characteristic form having substantial amounts of lead azide entrapped as a guest compound within the crystalline lattice structure of the complex salt of basic lead picrate, said method comprising the steps of:

(I) dissolving and suspending in water a predetermined amount of picric acid;

(H) adding to solution of picric acid with stirring slightly in excess of 2 gram moles of sodium hydroxide dissolved in water for each gram mole of picric acid;

(III) holding the temperature at 60 to 70 C., and adding to the solution with stirring for each gram mole of picric acid about 4 gram moles of a water solution of a water soluble lead salt selected from the group of lead salts of monobasic acids consisting of lead nitrate, lead acetate, lead formate, lead propionate, lead lactate, lead acrylate, lead methacrylate and lead butyrate;

(IV) adding with stirring and maintenance of temperature at 60 to 70 C., a water solution of between 1 and 4 gram moles of sodium azide for each gram mole of picric acid;

(V) continuing the stirring until an insoluble complex salt is precipitated;

(VI) separating the complex salt by filtering, washing and drying the precipitate.

37. A method as defined in claim 36, in which the water soluble lead salt is lead nitrate and in which there is included an additional step consisting of adding to the solution with stirring, after the addition of the sodium hydroxide solution and before the addition of the solution of the lead nitrate, slightly in excess of 1 gram mole for each gram mole of picric acid of a sodium salt of a monobasic acid selected from the group of monobasic acids consisting of acetic acid, formic acid, propionic acid, lactic acid, arcylic acid, methacrylic acid and butyric acid.

References Cited UNITED STATES PATENTS 3,293,091 12/1966 Kenney 149-26 X BENJAMIN R. PADGETT, Primary Examiner.

S. J. LECHERT, Assistant Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,431,156 March 4, 1969 Joseph F. Kenney It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 60, "governemnta1 should read governmental Coluu 4, line 68, after "basic", first occurrence, insert lead Column 6, line 2, "picate" should read picrate Column 7, line 10, cancel "a". Column 12, line 18, "All" should read Add line 61, "contaning" should containing line 74, "for" should read form Column 13, line 3, "lacate" should read lactate line 20, methacrylate" should read nitrate line 47, after "lead", third occurrence, insert azide line 73, after "lead", second occurrence, 1 insert azide Column 14, line 4, should be a period; line 65, "arcylic" should read acrylic:

Signed and sealed this 31st day of March 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

